This document describes a novel two-way wireless repeater and booster.
Most 3G and so called 4G systems (4G systems are mostly based on Orthogonal Frequency Division Multiplexing (OFDM) modulation) support high data rates, and as such have communication channels much larger in bandwidth (BW) compared to the 2G systems such as GSM. For example, a Wideband Code Division Multiple Access (WCDMA) channel at 5 MHz is 25 times larger than the GSM 200 kHz, while a WiMax channel BW is larger by 50 times or more.
While the aforementioned operation is true about a single communication channel, the Global System for Mobile (GSM) Frequency Hopping (FH) feature enables a GSM device to hop the full allocated spectrum, meaning a single GSM channel will, in the course of a session, operate on much broader BW than a static WCDMA or WiMax channel. This effectively means that a repeater or booster device, that does not have the capability of following the FH algorithm, has to “pass through” the entire spectrum in which the GSM communication channel is allowed to hop over, which is often the entire allocated spectrum to a given operator.
Further, the GSM allocated spectrum for a given operator may or may not be contiguous. Also it is desirable for a repeater and booster device to operate only on an “intended” network provider licensed frequencies, avoiding any operation in channels that are outside the licensed spectrum of the “intended” operator. This requirement means that a repeater (or booster) has to be designed to operate ONLY with a set of specific channels that may or may not be contiguous. FIG. 2 illustrates an example of such a scenario, where a given operator in a given area has three 10 MHz non-contiguous bands, totaling 30 MHz (15 MHz uplink and 15 MHz downlink), and where a GSM derived network can frequency hop on any 75 available channels. Ideally, the repeater shown in FIG. 2 will select, boost and repeat only the channels of interest, as shown.
Further still, since the repeated spectrum is now 15 MHz in a given direction, a digital link between the Network and the User units will require much larger operating BW (15×2×2×10=600 Mbs/s one way) which, although possible, may not be practical for a small consumer device. It may also be difficult to meet spectral regulations and regulatory requirements such as Dynamic Frequency Selection (DFS) and spectral emission mask in the unlicensed band, if large portions of the spectrum are concurrently used. Therefore, an OFDM based link (or any other digitally modulated link) may not be the most appropriate solution for the middle hop between the Network and the User units.